From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Antonio Quartulli Date: Sat, 21 May 2016 17:48:17 +0800 Message-Id: <20160521094817.401-1-a@unstable.cc> Subject: [B.A.T.M.A.N.] [PATCH stable-4.6] batman-adv: Fix double neigh_node_put in batadv_v_ogm_route_update List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: stable@vger.kernel.org Cc: b.a.t.m.a.n@lists.open-mesh.org, Antonio Quartulli From: Sven Eckelmann The router is put down twice when it was non-NULL and either orig_ifinfo is NULL afterwards or batman-adv receives a packet with the same sequence number. This will end up in a use-after-free when the batadv_neigh_node is removed because the reference counter ended up too early at 0. Fixes: 9323158ef9f4 ("batman-adv: OGMv2 - implement originators logic") Signed-off-by: Sven Eckelmann Signed-off-by: Antonio Quartulli --- This patch is skipping netdev and is being sent directly to stable in accordance with David S. Miller[1]. The reason is that this patch applies only on linux-4.6 and not on linux-4.7/net because it was "accidentally" fixed by a refactoring commit (more details in [2]). It addresses a reference imbalance which systematically leads to a use-after-free and then a kernel crash. Cheers, [1] https://www.mail-archive.com/b.a.t.m.a.n@lists.open-mesh.org/msg15258.html [2] https://www.mail-archive.com/b.a.t.m.a.n@lists.open-mesh.org/msg15252.html net/batman-adv/bat_v_ogm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c index d9bcbe6e7d65..91df28a100f9 100644 --- a/net/batman-adv/bat_v_ogm.c +++ b/net/batman-adv/bat_v_ogm.c @@ -529,8 +529,10 @@ static void batadv_v_ogm_route_update(struct batadv_priv *bat_priv, goto out; } - if (router) + if (router) { batadv_neigh_node_put(router); + router = NULL; + } /* Update routes, and check if the OGM is from the best next hop */ batadv_v_ogm_orig_update(bat_priv, orig_node, neigh_node, ogm2, -- 2.8.3